mitt romney and barack obama perform tomorrow night. >> just in time, on, i guess, the eve of the debate, there's a new poll out. tell us about it. >> it is, carol. look at this new cnn poll of polls, calculated an hour ago. calculating together six different polls, showing the race say dead heat right now. barack obama has a very short lead right now over mitt romney nationally. this is what the national numbers look like, 49 to 46 right now, barack obama. we should note that this race is really going to be won and lost in states where i stand right now. colorado. other states such as nevada, virginia, ohio. these are very important states that the candidates will be focusing all of their time on as we head into the spring, into november. carol? >> mark preston, reporting live from denver. >>> cnn has learned months before the 9/11 attack in libya that killed the u.s. ambassador and three other americans, there were security concerns surrounding the diplomatic mission in benghazi. the white house first called the attack spontaneous, the one in benghazi that killed the amba